Abstract : Atmospheric density changes as observed from nine soundings taken over a three and one half hour time span are described. Arcasonde, Datasonde and inflatable falling sphere sensors were used to determine the density structure. There was general agreement between the mean densities derived from the spheres and the Arcasonde and Datasonde sensors; however, the sphere data show more variation from sounding to sounding. A paired data test using 42 soundings showed that the first estimate of the standard deviation of sensor random error of density for the Arcasonde was 0.75%, for the Datasonde 0.77%, for the sphere 2.86% and for the Arcasonde-Datasonde comparisons 1.38%. In an analysis of variance procedure, the percentage change in atmospheric density over various time spans was determined. (Author)